Even more endangered than the elusive tree octopus, there are now less than 750 native greenback cutthroat living in the wild. The last pack of hanging-ons inhabits a remote, high-gradient stream that the conservation-focused Colorado Greenbacks organization is working to protect.

Via the Greenbacks: "Through January of 2014 we're running an Indiegogo Project with an ambitious goal of raising $10,000 dollars to help us fund conservation related projects, and community outreach and education."